Electron transfer complex structure

The P450BM3 electron transfer complex structure also is consistent with mutagenesis and... 

Sevrioukova IF, Li H, Zhang H, et al. Structure of a cytochrome P450-redox partner electron-transfer complex. Proc Natl Acad Sci U S A 1999 96 1863-1868. 

Sevrioukova, I. F., Li, H., Zhang, H., Peterson, J. A., and Poulos, T. L., 1999, Structure of a cytochrome P450-redox partaer electron-transfer complex Proc. Natl. Acad. Sci. U. S. A. 96 1863nl868. 

Structural and catalytic properties of the eight flavin electron transfer complexes... 

Methylamine Dehydrogenase Structure and Function of Electron Transfer Complexes... 

Chen, L., Durley, R., Mathews, F. S., and Davidson, V. L., 1994, Structure of an electron transfer complex Methylamine dehydrogenase, amicyanin and cytochrome c-551i. Science 264 86990. 

The foeus of this chapter is the soluble electron transfer complex formed between the nieotinamide-independent trimethylamine dehydrogenase (TMADH) and eleetron transferring flavoprotein (ETF). Recent studies of this physiological electron transfer complex have provided invaluable insight into (i) the mechanisms of inter and intraprotein electron transfer between flavin and Fe/S centers, (ii) the role of dynamics in interprotein electron transfer and (hi) quantum meehanieal mechanisms for the cleavage of substrate C-H bonds and the subsequent transfer of reducing equivalents to flavin redox centers. Brief mention is made of early structural and cofactor analyses for this redox system, but more detailed accounts of this work can be found in earlier reviews on the subjeet (e.g. Steenkamp and Mathews, 1992). 

A major handicap to our detailed rmderstanding of the electron transfer reactions between TMADH and ETF is the lack of a crystallographic structure for ETF. Crystals of ETF have been isolated (White et al., 1994), but to date no structure for the protein has been reported. A homology model for ETF, however, has been constructed based on the crystallographic structure of human ETF (Roberts et al., 1996), and this model has been used to create a model of the electron transfer complex formed between TMADH and ETF (Chohan et al., 1998) (Figure 7). ETF comprises two subunits, which in turn form three domains. Domain I comprises the N-terminal region of the a-subunit, domain II comprises the C-terminal... 

Chohan, K. K., Scrutton, N. S., and Sutcliffe, M. J., 1998, Major structural reorganisation most likely accompanies the transient formation of a physiological electron transfer complex, Prot. Pept. Lett 5 2319236. 

Figure 16 Structure of the ternary electron-transfer complex of MADH, amicyanin, and cytochrome c-551 (pdb code 2MTA). The copper atom of amicyanin is 9.4 A from the edge of Trp 108 in the electron donor MADH and 24.7 A from the electron acceptor iron atom in cytochrome c-551...

A long-range electron transfer is possible in this reaction, as in alkali metal atom reactions. However, the resulting electron-transfer complex Ba NO does not correlate to the ground-state products BaO which has the structure Ba +0. Moreover, the NOJ ion is stable and its dissociation into NO 4- 0 is endoergic. Hence the Ba "NOj complex may survive for many rotational periods despite the availability of a very exoergic reaction channel. This is expected to dissociate after the transfer of the second valence electron of barium, which is probably hindered by an energy barrier. 

Electron Transfer Reactions— Structure, Properties and Reactivity of Tris(bidentate chelate) cobalt(ll/III) Complexes... 

Fig. 2. Electron micrographs of phycobilisomes in the red alga Rhodella violacea (A) and phycobilisomes isolated from Porphyridium cruentum (B). (C) shows a membrane model consisting of the electron-transfer complexes of PS I, PS II, the cytochrome bet complex, the ATP synthase, CFq CFi, and the phycobilisomes. (A) and (C) from MOrschel and Rhiel (1987) Phycobilisomes and thylakoids The light-harvesting system of cyanobacteria and red algae. In JR Harris and RW Horne (eds) Membranous Structure, pp 216, 248. Acad Press (A) kindly furnished by Dr. Erhard Mbrschei and (B) kindly furnished by Dr. Alexander Glazer.

For simple outer-sphere self-exchange reactions of transition-metal complexes in both aqueous and polar organic solvents, is dominated by AVj and hence is expected to be negative, regardless of whether electron transfer is fully adiabatic. In cases in which this expectation is not realized, there is usually an identifiable departure from a simple outer-sphere mechanism attributable to inner-sphere pathways, cationic catalysis of anion-anion electron transfer, or structural distortions associated with spin multiplicity changes. Thus, AV can serve as a mechanistic criterion. 

---